Impeller

ABSTRACT

An impeller includes a wheel hub and a plurality of blades. The blade has a blade root, and the blade connects to the wheel hub through the blade root. The blades have different lengths. Each blade has an included angle between the blade root and the wheel hub, and the included angles of the blades are different. A centroid of the blades is located at an axis center of the impeller. The impeller is further configured with a blade reinforcement structure.

CROSS REFERENCE TO RELATED APPLICATIONS

This Non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 201720192846.9 filed in People's Republic of China on Mar. 1, 2017, the entire contents of which are hereby incorporated by reference.

BACKGROUND Technology Field

This disclosure relates to an impeller and, in particular, to an impeller having blades with different lengths and included angles.

Description of Related Art

The heat dissipation device has been widely applied in various electronic devices. In particular, the heat-dissipating fan has low cost, high heat-dissipating effect, and high reliability, so it is one of the popular heat dissipating devices for various systems.

In order to design a proper heat-dissipating fan, the provided air quantity, air pressure and/or rotation speed must satisfy the requirements. Moreover, to decrease the generated noise and the abnormal sound as the fan rotates is also a very important issue. If the rotating heat-dissipating fan generates laud noise, abnormal sound and wind noise, the user may be affected by these noises and sound and feel uncomfortable. In other words, if the rotating heat-dissipating fan generates smaller noise, the user may much satisfy with the product.

Therefore, it is an important subject to provide a heat dissipation device that can effectively dissipate the heat and decrease the noise of the fan.

SUMMARY

In view of the foregoing, an objective of the present disclosure is to provide an impeller and a fan that can effectively dissipate the heat and decrease the noise generated by the blades.

To achieve the above objective, the present disclosure discloses an impeller including a wheel hub and a plurality of blades. Each of the blades has a blade root, and each blade connects to the wheel hub through the blade root. The blades have different lengths, and each blade has an included angle between the blade root and the wheel hub. The included angles of the blades are different, and a centroid of the blades is located at an axis center of the impeller.

In one embodiment, the included angles of the blades are changed gradually in order, and the lengths of the blades are gradually changed corresponding to the gradually changed included angles, so that the centroid of the blades is located at the axis center of the impeller.

In one embodiment, the lengths of the blades and the included angles of the blades are gradually changed with an equal difference.

In one embodiment, a difference of the lengths of two adjacent blades is 1%˜10%.

In one embodiment, a difference of the included angles of two adjacent blades is 1%˜10%.

In one embodiment, noise frequencies caused by the blades are different.

In one embodiment, the impeller further includes a blade enhancement structure disposed around the wheel hub and connecting to the blades.

In one embodiment, the blades are a balanced asymmetric structure, so that the centroid of the blades is located at the axis center of the impeller.

To achieve the above objective, the present disclosure also discloses an impeller includes a wheel hub, a plurality of blades and a blade enhancement structure. Each of the blades has a blade root, and the blade connects to the wheel hub through the blade root. The blades have different lengths, and each blade has an included angle between the blade root and the wheel hub. The included angles of the blades are different, and a centroid of the blades is located at an axis center of the impeller. The blade enhancement structure is disposed around the wheel hub and connects to a part of the blades.

In one embodiment, the blade enhancement structure is disposed on two or more of the blades.

In one embodiment, the included angles of the blades are changed gradually in order, and the lengths of the blades are gradually changed corresponding to the gradually changed included angles, so that the centroid of the blades is located at the axis center of the impeller.

In one embodiment, a difference of the lengths of two adjacent blades is 1%˜10%.

In one embodiment, a difference of the included angles of two adjacent blades is 1%˜10%.

In one embodiment, noise frequencies caused by the blades are different.

In one embodiment, the blades are a balanced asymmetric structure, so that the centroid of the blades is located at the axis center of the impeller.

In one embodiment, the blade enhancement structure is discontinuously disposed around the wheel hub to connect the blades.

As mentioned above, the impeller of the disclosure includes a wheel hub and a plurality of blades. Each of the blades has a blade root, and the blade connects to the wheel hub through the blade root. The blades have different lengths, and each blade has an included angle between the blade root and the wheel hub. The included angles of the blades are different, and a centroid of the blades is located at an axis center of the impeller. Accordingly, when the impeller and the fan are in operation to effectively dissipate heat, the generated noise can be sufficiently decreased, thereby increasing the product satisfaction of the user.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will become more fully understood from the detailed description and accompanying drawings, which are given for illustration only, and thus are not limitative of the present disclosure, and wherein:

FIG. 1A is a schematic diagram of a fan according to an embodiment of the disclosure;

FIG. 1B is a schematic diagram of an impeller according to an embodiment of the disclosure;

FIG. 1C is a top view of the impeller of FIG. 1B;

FIG. 1D is a top view of the impeller of FIG. 1B;

FIG. 2A is a schematic diagram of an impeller according to another embodiment of the disclosure;

FIG. 2B is a top view of the impeller of FIG. 2A;

FIG. 3A is a schematic diagram of an impeller according to another embodiment of the disclosure; and

FIG. 3B is a top view of the impeller of FIG. 3A.

DETAILED DESCRIPTION OF THE DISCLOSURE

The present disclosure will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.

FIG. 1A is a schematic diagram of a fan according to an embodiment of the disclosure, FIG. 1B is a schematic diagram of an impeller according to an embodiment of the disclosure, and FIGS. 1C and 1D are top views of the impeller of FIG. 1B. To be noted, the lengths and shapes of the blades and the impeller 1 of FIGS. 1A to 1D are for illustrations only, and they can be modified based on the environment and the heat source of the target electronic device.

As shown in FIG. 1A, the impeller 1 is configured in a heat-dissipating fan. The fan can be applied to dissipate heat of any electronic device such as, for example but not limited to, a computer, power device, CPU, VGA, IC, mainboard, or lamp, which can generate a lot of heat. The fan can be configured to force the air flowing through the heat sink contacting with the electronic device, thereby removing the heat generated by the electronic device or heat source.

In this embodiment, the fan includes an impeller 1 and a motor M. The impeller 1 has the technical features of the embodiments described hereinafter. The motor M is connected to the wheel hub of any of the following embodiments. The impeller 1 includes a wheel hub 11 and a plurality of blades 12. In addition, the fan further includes an upper housing, a lower housing, a bearing and a driving device (the motor M). One end of each blade 12 (the blade root) is connected to the wheel hub 11, and the other end of each blade 12 extends from the wheel hub 11 and is curved. Accordingly, the blades 12 are distributed around the wheel hub 11, and the wheel hub 11 is rotatably connected to a stator of the motor M. The stator can drive the wheel hub 11 to rotate, thereby rotating the blades 12 to induce the air convection for dissipating heat. To be noted, the detailed technical features of the wheel hub and impeller of the fan of this embodiment can be referred to the following embodiments, so the detailed descriptions thereof will be omitted here.

The wheel hub 11 and the impeller 12 can be formed as one piece by plastic injection, and the material thereof can be PP, ABS resin, PBT, and the likes. Moreover, the blades can be formed by composite materials (e.g. added with glass fibers) for increasing the hardness thereof. In addition, the wheel hub 11 and the impeller 12 can also be made of metals such as aluminum alloy. Since the metal blades have less deformation during high-speed rotation than the plastic blades, the metal blades can be made longer and have better rigidity than plastic blades, thereby extending the lifetime of the impeller.

Referring to FIG. 1B, the impeller 1 includes an axis C1, and the number of the blades 12 can be optionally odd or even. If the number of the blades 12 is even, the blades 12 are symmetrically disposed around the axis C1. In other words, a line connecting two opposite blades 12 (blade roots) will pass through the axis C1. In this case, the vibrations of the opposite blades 12 can be delivered to each other so as to generate the undesired resonance, which can shorten the lifetime of the wheel hub 11 and increase the noise as the impeller 1 is rotating. If the number of the blades 12 is odd, the blades 12 are asymmetrically disposed around the axis C1. In other words, a line connecting any two blades 12 (blade roots) does not pass through the axis C1. In this case, although the vibrations can be delivered between the blades 12, the different vibration directions can prevent the stacking of the vibration energies.

When the air is applied with periodic interferences, the noises with the same vibration frequency can be generated. For example, the rotating impeller and blades (rotor) of the heat dissipating fan usually provide the periodic interferences to induce the airflow for dissipating heat. The noises with the same vibration frequency are transmitted via air and form a single frequency noise. Alternatively, the air can be affected by the pressure variation caused by the movement of the blades and the pressure field so as to generate the narrow-frequency noise. Besides, the gap between the fan frame and the blades can also induce the generation of the narrow-frequency noise.

When the conventional heat dissipating fan is installed in an electric device, the relative wind flows of the blades and the air holes of the machine case can generate additional high-frequency noise. This will obviously increase the noise of the fan when the impeller is operated along or the fan is installed in the device. In the conventional heat dissipating fan, the blades usually have the same interval, the same gap or the same included angle. According to this design, the sound energies will be stacked on the frequency obtained by the product of the blade number and the rotating number. Thus, the sound energy of this frequency is obviously higher than the sound energies of adjacent frequencies. This can also generate undesired noise (the resonance noise), which will induce a negative effect to the lifetimes of the electronic device and the fan.

When the sound energy of the noise frequency is higher than the sound energies of adjacent frequencies by 7 dB, humans can hear an obvious uncomfortable sound. This will cause the bad feeling and bad image of the users. To solve this noise problem, the blades can be designed with a certain irregularity. Accordingly, the blades 12 of the impeller 1 of this embodiment have a design different from the structure of the conventional heat-dissipating fan.

Referring to FIGS. 1B to 1D, the number of blades 12 of the impeller 1 is n, such as the blades 121, 122, 123, . . . , and 12 n. In this embodiment, the number of blades 12 of the impeller 1 is 21 (21 blades). As shown in FIG. 1D, each of the blades 121, 122, 123, . . . , and 1221 has a blade root, a blade middle, and a blade tail. For example, the blade 121 has a blade root 121 a, a blade middle 121 b, and a blade tail 121 c. The blades 121˜1221 are connected to the wheel hub 11 through the blade roots 121 a˜1221 a, respectively. Each of the blades 121˜1221 has an included angle with respect to the wheel hub 11 (e.g. the included angles θ1, θ2, θ3, . . . , and θ21) and a length (e.g. the lengths R1˜R21). For example, the length R1 is equal to the sum of the lengths of the blade root 121 a, the blade middle 121 b and the blade tail 121 c. Herein, the lengths R1˜R21 are different, and the included angles θ1˜θ21 are also different.

In this embodiment, the lengths of the blade roots 121 a-1221 a are the same and the lengths of the blade middles 121 b˜1221 b are also the same, but the lengths of the blade tails 121 c˜1221 c are different. Accordingly, the total lengths R1˜R21 of the blades 121˜1221 are different. Taking the blades 121 and 122 as an example, the lengths of the blade roots 121 a and 122 a are the same and the lengths of the blade middles 121 b and 122 b are also the same, but the lengths of the blade tails 121 c and 122 c are different. Accordingly, the total lengths R1 and R2 of the blades 121 and 122 are different. The included angles θ1˜θ21 are between the blade roots 121 a˜1221 a and the wheel hub 11, respectively. In addition, the distances Y1˜Y21 between the blade tails 121 c˜1221 c of the blade 121˜1221 are different. To be noted, when the impeller is configured with a lot of blades, the distances may approach to the lengths of the direct lines between every two adjacent blade tails.

In this embodiment, the lengths R1˜R21, the included angles θ1˜θ21, and the distances Y1˜Y21 of the blades 121˜1221 are gradually changed, which is different from the structural of the conventional blades disposed on the wheel hub with the same intervals. In addition, the lengths R1˜R21 of the blades 121˜1221 are gradually increased corresponding to the gradually increased included angles θ1˜θ21. Accordingly, the blades of this embodiment are different from the conventional blade design, which have an identical length. In other words, as the included angles θ1˜θ21 and the distances Y1˜Y21 of the blades 121˜1221 are gradually increased, the lengths R1˜R21 of the blades 121˜1221 are also gradually increased, and vice versa.

In addition, the blades 121˜1221 are sequentially disposed on the periphery of the wheel hub 11 in counterclockwise. Of course, in other embodiments, the blades 121˜1221 can be sequentially disposed on the periphery of the wheel hub 11 in clockwise. This disclosure is not limited.

In this embodiment, the lengths R1˜R21 of the blades 121˜1221 are gradually changed with an equal difference, and so are the distances Y1˜Y21 and the included angles θ1˜θ21 of the blades 121˜4221. In general, this disclosure has a gradually changed design with an equal difference. In more detailed, the included angles of the blades 121˜1221 fit the following equations: θ2=θ1+d, θ3=θ1+2d, θ4=θ1+3d, . . . , and θ21=θ1+20d, and d is a constant angle. In addition, the distances between the blades fit the following equations: Y2=Y1+Z, Y3=Y1+2Z, Y4=Y1+3Z, . . . , and Y21=Y1+20Z, and Z is a constant length. The lengths R1-R21 are gradually increased corresponding to the included angles θ1˜θ21 as defined above. In other words, the lengths R1˜R21 of the blades fit the following equations: R2=R1+D, R3=R1+2D, R4=R1+3D, . . . , and R21=R1+20D, and D is a constant length.

In this embodiment, the blades 12 are disposed on the periphery of the wheel hub 11 in counterclockwise, and the included angles θ1˜θ21, the distances Y1˜Y21 and the lengths R1˜R21 of the blades 121˜1221 are gradually changed with an equal difference. In practice, the differences of the lengths R and the included angles θ of two adjacent blades are 1%˜10%, and preferably 3%˜7%. Accordingly, the variation of the lengths R and the included angles θ of the blades 12 can be controlled within a certain range. In addition, the irregularity of the blades 12 can be further increased by the design of different included angles, different lengths and different distances of the blades.

Besides, in the design of the disclosure, the centroid C2 of the blades 121˜1221 is located at the axis center C1 of the impeller 1. In other words, the blades 12 of the disclosure have a balanced asymmetric structure design. Accordingly, the blades 12 are arranged asymmetrically, and the centroid C2 of the blades 121˜1221 and the axis center C1 of the impeller 1 are the same. The centroid is in the center. In this design, the entire device can be kept stable when the impeller 1 is rotated in high speed, so that the blades will not be broken during the rotation and the abnormal sound can be prevented.

In this embodiment, the irregular blades 12 can be arranged with a weighting design for achieving the rotation balance of the impeller 1. In more detailed, the blades with shorter lengths R and lighter weights can be arranged with a higher density (smaller distances Y and included angles θ), while the blades with longer lengths R and heavier weights can be arranged with a lower density (greater distances Y and included angles θ). Accordingly, the centroid C2 of the entire blades 12 can be located at the axis center C1 of the impeller 1. In practice, since the lengths and included angles of the blades are different, it is preferred to perform proper blade length detection, blade distance detection, blade angle detection and rotation balance detection for the impeller 1. Accordingly, the blades 12 of the above design can achieve the rotation balance of the impeller 1.

In other embodiments, the lengths R1˜R21, the included angles θ1˜θ21 and the distances Y1˜Y21 of the blades 121˜1221 can be arranged by any design other than the above-mentioned gradually changed design. Any design that allows the blades 121˜1221 to rotate in a balance state and keeps the centroid locating at the axis center of the impeller 1 can be used in this disclosure.

In practice, the blades 121˜1221 are connected to the wheel hub 11 through the blade roots 121 a˜1221 a, respectively, and the blades 121˜1221 are disposed with gradually changed lengths R, included angles θ, and distances Y. Accordingly, when the impeller 1 is rotating, the noise frequencies f1, f2, f3, . . . , and f21 generated by the blades 121˜1221 are different. This is different from the conventional impeller having blades with regular lengths, distances and included angles that can generate noise frequencies of the same frequency. In the design of the disclosure, the generated noise frequencies can be effectively dissipated, and thus the noise frequencies with a single frequency are not generated. Since the noise frequencies of the blades are different, the sound energies will not stacked on a specific frequency. This feature can prevent to generate the sound energy of the specific frequency that is obviously higher than other sound energies of the adjacent frequencies, thereby avoiding the undesired resonance noise.

FIG. 2A is a schematic diagram of an impeller according to another embodiment of the disclosure, and FIG. 2B is a top view of the impeller of FIG. 2A. As shown in FIG. 2A, most components and the relations thereof of the impeller 2 are the same as the above-mentioned impeller 1. Thus, FIGS. 2A and 2B only show the part of the impeller 2 different from the impeller 1. Different the impeller 1, the impeller 2 further includes a blade enhancement structure 23 disposed around the wheel hub 21 and connecting to the blades 22. In this embodiment, the blade enhancement structure 23 is an annular structure disposed around the wheel hub 21 for fixing and connecting the blades 22. This configuration can fix and enhance the blades 22 so as to increase the structural strength.

In this embodiment, similar to the blades 12, the lengths R, distances Y and the included angle θ of the blades 22 are disposed based on the gradually changed design. In detailed, the blades 221˜2221 with different lengths R1˜R21 are disposed on the periphery of the wheel hub 21 with included angles θ1˜θ21 in counterclockwise. Herein, the lengths R1˜R21, the distances Y1˜Y21 and the included angles θ1˜θ21 are gradually increased instead of being changed with an equal difference. That is, R1<R2< . . . <R21, θ1<θ2< . . . <θ21, and Y1<Y2< . . . <Y21.

In another aspect, the impeller may further include a blade enhancement structure disposed around the wheel hub and connecting the blades. Herein, the included angles and the lengths of the blades are gradually increased, so that the centroid of the blades is located at the axis center of the impeller. The lengths and included angles of the blades are gradually changed with an equal difference. The difference of the lengths of two adjacent blades is 1%˜10%, and the difference of the included angles of two adjacent blades is 1%˜10%. The noise frequencies caused by the blades are different. The blades have a balanced asymmetric structure, so that the centroid of the blades is located at the axis center of the impeller.

Accordingly, the noise frequencies caused by the blades 221˜2221 are different, so that the generated noise frequencies of the blades 22 in the impeller 2 can be effectively dissipated. When the blades rotate to generate the airflow to dissipate the heat, the noise frequencies are different since the lengths, distances and included angles of the blades are irregular. In addition, the noise frequencies with a single frequency are not generated. Since the noise frequencies of the blades are different, the sound energies will not stacked on a specific frequency. This feature can prevent to generate the sound energy of the specific frequency that is obviously higher than other sound energies of the adjacent frequencies, thereby avoiding the undesired resonance noise. Moreover, the blade enhancement structure 23 is disposed around the wheel hub 21 and fixes and connects to the blades 22. This configuration can increase the rigidity and durability of the blades, so that the impeller 2 can have a longer lifetime.

The other technical features and operation of the impeller 2 can be referred to the impeller 1 of the previous embodiment, so the detailed description thereof will be omitted.

FIG. 3A is a schematic diagram of an impeller according to another embodiment of the disclosure, and FIG. 3B is a top view of the impeller of FIG. 3A.

As shown in FIGS. 3A and 3B, most components and the relations thereof of the impeller 3 are the same as the above-mentioned impeller 2. Different the impeller 2, the blade enhancement structure 33 of the impeller 3 is not an annular structure but is discontinuously disposed around the wheel hub 31 for fixing and connecting the blades 32. In more detailed, the blade enhancement structure 33 is disposed at the places of the blades 32 with large changes of the lengths R, the included angles θ and the distances Y. For example, the blades 32 with a change greater than 7% are configured with the blade enhancement structure 33. In addition, the blade enhancement structure 33 is disposed on two or more blades. Accordingly, the blade enhancement structure 33 is discontinuously disposed around the wheel hub 31 for connecting the blades 32, thereby fixing and enhancing the blades 32 so as to increase the structural strength.

In this embodiment, the lengths R, the distances Y and the included angles θ are gradually increased instead of being changed with an equal difference. That is, R1<R2< . . . <R21, θ1<θ2< . . . <θ21, and Y1<Y2< . . . <Y21. Accordingly, the noise frequencies caused by the blades 32 are different, so that the generated noise frequencies of the blades 32 can be effectively dissipated. When the blades 32 of the impeller 3 rotates, the noise frequencies with a single frequency are not generated. This configuration can prevent the undesired resonance noise. Besides, the blade enhancement structure 33 is configured at the places of the blades 32 with larger changes for fixing and connecting the blades 32. This configuration can also increase the rigidity and durability of the blades, so that the impeller 3 can have a longer lifetime.

The other technical features and operation of the impeller 3 can be referred to the impeller 2 of the previous embodiment, so the detailed description thereof will be omitted.

In summary, the impeller of the disclosure includes a wheel hub and a plurality of blades. Each of the blades has a blade root, and the blade connects to the wheel hub through the blade root. The blades have different lengths, and each blade has an included angle between the blade root and the wheel hub. The included angles of the blades are different, and a centroid of the blades is located at an axis center of the impeller. Accordingly, when the impeller and the fan are in operation to effectively dissipate heat, the generated noise can be sufficiently decreased, thereby increasing the product satisfaction of the user.

Although the disclosure has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the disclosure. 

What is claimed is:
 1. An impeller, comprising: a wheel hub; and a plurality of blades, wherein each of the blades has a blade root, the blade connects to the wheel hub through the blade root, the blades have different lengths, each of the blades has an included angle between the blade root and the wheel hub, the included angles of the blades are different, and a centroid of the blades is located at an axis center of the impeller.
 2. The impeller of claim 1, wherein the included angles of the blades are changed gradually in order, and the lengths of the blades are gradually changed corresponding to the gradually changed included angles, so that the centroid of the blades is located at the axis center of the impeller.
 3. The impeller of claim 2, wherein the lengths of the blades and the included angles of the blades are gradually changed with an equal difference.
 4. The impeller of claim 2, wherein a difference of the lengths of adjacent two of the blades is 1%˜10%.
 5. The impeller of claim 2, wherein a difference of the included angles of adjacent two of the blades is 1%˜10%.
 6. The impeller of claim 1, wherein noise frequencies caused by the blades are different.
 7. The impeller of claim 1, further comprising: a blade enhancement structure disposed around the wheel hub and connecting to the blades.
 8. The impeller of claim 1, wherein the blades are a balanced asymmetric structure, so that the centroid of the blades is located at the axis center of the impeller.
 9. An impeller, comprising: a wheel hub; a plurality of blades, wherein each of the blades has a blade root, the blade connects to the wheel hub through the blade root, the blades have different lengths, each of the blades has an included angle between the blade root and the wheel hub, the included angles of the blades are different, and a centroid of the blades is located at an axis center of the impeller; and a blade enhancement structure disposed around the wheel hub and connecting to a part of the blades.
 10. The impeller of claim 9, wherein the blade enhancement structure is disposed on two or more of the blades.
 11. The impeller of claim 9, wherein the blade enhancement structure is discontinuously disposed around the wheel hub to connect the blades. 